CPSC-102: Computing and Algorithms II

Programming Assignment 1

Summer 1998

File Input

This file will contain at most 20 descriptions of movie videos. Each video will be represented by 4 lines:

• The first line contains a string representing the title of the movie.
• The second line contains an integer representing the year the movie was released.
• The third line contains a integer representing the running time of the movie (in minutes).
• The fourth line contains the string ``true'' or ``false'', answering the following question: Is this video currently in the store (i.e. not checked out)?

Interactive Input

• Search the database for a movie. If selected, the program should ask the user for the title of the movie. Using that ID, the program should print the video's information if it exists in the database, and an appropriate message if it does not.
• Print the database. If selected, the program should print the entire contents of the database in an appropriate format.

• Exit the program. If selected, the program should terminate.

Your program should validate input whenever possible. For example:

• You should check that the user provides a single argument on the command line.

• You should check that the user provides valid options during the interactive phase of the program.

Your program should be designed with modifiability in mind. We will be revising and extending this program several times throughout the semester; consequently, it is to your benefit to design your program in as modular a fashion as possible. In particular:

• You should define a class Video which contains members corresponding to a given video, and methods which deal with books (e.g. create, print, getTitle).
• You should define a class Database which contains members which allow one to manipulate a collection of \texttt{Video} objects (e.g. search, print). The Database class should never access the internal members of the Video class directly.
• You should define a class Prog1 with a main method which calls the Database class to perform the required operations. The Prog1 class should never access the members of the other classes directly.

A Sample Session

Star Trek: First Contact
1996
110
true
Citizen Kane
1941
119
true
Chariots of Fire
1981
123
false
Blues Brothers, The
1980
133
false

nova -: java Prog1 datafile
Welcome to the Kettering Video Database: Version 1.0

Current available commands:
1 --> Search for a video
2 --> Print all videos
9 --> Exit
Your choice? 2

Database:

Title:    Star Trek: First Contact
Released: 1996
Runtime:  110 minutes
Available:  Yes

Title:    Citizen Kane
Released: 1941
Runtime:  119 minutes
Available:  Yes

Title:    Chariots of Fire
Released: 1981
Runtime:  123
Available:  No

Title:    Blues Brothers, The
Released: 1980
Runtime:  133
Available:  false

End of Database.

Current available commands:
1 --> Search for a video
2 --> Print all videos
9 --> Exit
Your choice? 1

Title to find? Chariots of Fire

Title:    Chariots of Fire
Released: 1981
Runtime:  123
Available:  No

Current available commands:
1 --> Search for a video
2 --> Print all videos
9 --> Exit
Your choice? 1

Title to find? Titanic

The specified video could not be found.

Current available commands:
1 --> Search for a video
2 --> Print all videos
9 --> Exit
Your choice? 9
nova -: 

Notice that this is a sample run; your run may operate differently as long as it fulfills the requirements outlined above.

You should create several input files in order to test your program thoroughly; do not assume that simply testing the program on the input file shown above is sufficient to test your program. (What happens if the input file is empty? What if it contains too many entries? How will you handle these cases?)

Submitting Your Program

In addition, you must deliver to the instructor a printout of your program files at the start of class on Friday, 17 July 1998 (2nd Friday).

Notes

1. Start Early! The intent of this program is to make sure you are familiar with Java and our Java environment. However, there are some new features in the program (e.g. file input, exception handling), and some new style requirements, that may catch you if you are not careful.

2. The currently installed version of the Java Development Kit is version 1.1.6. To make sure that you are using the correct version, type which javac at a Unix prompt. If the answer returned is /usr/local/lang/jdk1.1.6/bin/javac, you are using the correct version. If this answer returned is anything else, delete any reference to the JDK from your .cshrc files, logout, and login again. If this does not work, see the instructor for assistance.
3. Recall that the main method for a Java program begins as follows:
   public static void main(String[] args) ...

   args is an array of strings; the elements of this array are the command-line arguments given to this program. args.length gives the length of the array, i.e., the number of command-line arguments supplied to the program.

4. Input and output in Java is handled via the standard Java classes. One convenient method for reading lines of input from the console and from files is the following:

   import java.io.*;
   ...
   BufferedReader console =
     new BufferedReader(new InputStreamReader(System.in));
   BufferedReader fileInput =
     new BufferedReader(new FileReader("foo.bar"));
   ...
   String inputLine = console.readLine();
   

   Note that FileReader throws a FileNotFoundException, which must be caught in your program.

   For more information on all of the above, see the Java API in file:/usr/local/lang/jdk1.1.6/docs/index.html on the Unix machines, or http://java.sun.com/products/jdk/1.1/docs/index.html.